6.1 Normal Case (4)

The game has now formally ended under territory rules I, and Dia. 6-1-4
shows the result. Black's score is 32 (52 points of territory minus
20 prisoners). White's score is 33 (43 points of territory minus 10
prisoners). White wins by one point.

Under area rules III, since Black can make the first pass after White
288, the last competitive move is made by White. If the game is then
finished as in Dia. 6-1-4, Black's score is 180 and White's is 181.
White wins by one point, giving the same result as under territory rules
I or traditional territory rules.*

Since the result of the moves after White 288 is obvious, the game can
be ended by agreement at White 288. In fact, it is possible to end the
game by agreement at White 274.

Under area rules II and territory rules III White wins by one point
as in Dias. 6-1-1 to 6-1-4. Under area rules III and territory rules
I, however, White can win by two points by leaving the ko unconnected.
Reference Diagram 2 shows one possible sequence.

Reference Diagram 2 (1-26)ko: 13, 16, 19, 22, 25. pass: 27

Black has just three ko threats left at A, B, and C. White has
five ko threats at D to H and two more at I, so he is in no danger
of losing the ko. Under area rules III White gets an extra point for
making the first pass. Under territory rules I White can leave the ko
open and claim a point of territory at 10, or connect the ko after the
preliminary end and receive a stone from Black.

This illustrates the point that by rewarding the player who passes
first, territory rules I and area rules III introduce a factor of skill
that is missing from both traditional territory rules and traditional
area rules.